Turkey says its military has inflicted significant losses in an attack on Kurdish rebels in northern Iraq, and it warns that such attacks across the border may continue.

Turkey did not say its ground troops actually crossed the border, however. Official statements give few details about Saturday's operation, but government and military officials speaking anonymously said Turkish artillery fired on Kurdish rebel positions close to the border, and that air strikes also may been involved.

An announcement posted on the Turkish army's web site says the attack was aimed at a group of 50 to 60 rebels operating in an area of northern Iraq, Cukurca town in Hakkari province, adjacent to Turkish territory, and also near the border with Iran.

The U.S. military said it has no information about any ground incursion by Turkey. Reports from the Kurdish side of the border - from both the regional government in northern Iraq as well as the PKK rebel group - deny that any attack took place, either by ground troops, artillery or Turkish warplanes.

Turkey says its intelligence pinpointed the rebel fighters' positions, and a military statement says such operations will continue, if necessary.

Prime Minister Recep Tayyip Erdogan announced Friday that his government has authorized the army to carry out cross-border operations against rebels from the outlawed Kurdistan Workers Party, who have staged repeated raids into southeastern Turkey this year. Turkey's parliament previously approved such tactics, and the army has had tens of thousands of troops stationed along the Iraqi border for weeks.

The United States and Iraq have urged Turkey not to send any military units into northern Iraq. They are concerned that could destabilize the relatively peaceful region.